In the utilization of machinery or apparatus, such as electric motors and equipment being driven thereby, it is frequently necessary to provide sound insulation to reduce the sound level emanating from the location of such equipment. To reduce the sound level, it is common practice to provide sound insulation material encasing or surrounding the source of the undesirable acoustic radiation. The insulation material may take the form of a molded sound-absorbing material having appropriate acoustic absorption characteristics. The use of such molded acoustic barriers generally requires molding techniques employing molds and processes to produce the sound absorbing acoustic barrier. Molded acoustic barriers also dictate the requirement of materials that may not have the desirable acoustic dampening characteristics; the requirement for molds and processing equipment also renders the molded acoustic barrier expensive and militates against modification or changes that require modified or new molds or processes.
A less expensive technique is the utilization of flat sheets or webs of acoustically absorbent material that is cut into various shapes to conform to an enclosure for surrounding the noise generating machinery. This latter technique is less expensive and does not require the creation of molds or the use of molding techniques to provide the necessary acoustic dampening.